Answer:
Hi!
The correct answer is 3 bits.
Explanation:
Each connected network needs a unique address.
If you borrow 3 bits from the host portion of an address then you have a combination of:
.000
.001
.010
.011
.100
.101
.110
.111
The borrowed address from the host portion, in this case, are 2³ = 8 address, this means that you have 3 address left before needing more bits.